Studies proposed for the first year of the Program Project Grant in clinical projects 3-5 will generate over 350 marrow, peripheral blood and cord blood samples (Tables 1,2,3). These samples will be distributed among the laboratories of the project leaders, core leaders and collaborators for assessment of phenotype, progenitor content, retroviral marking and evidence of contamination with malignant cells when relevant. The Sample Procurement Core (Core C) will support a centralized effort to procure and distribute samples generated by experiments proposed in Projects 3-5 to the appropriate research laboratories. Sample Procurement Core personnel will monitor patient entry into clinical trials and obtain required samples in a proactive fashion. Samples will be logged, and minimal processing (e.g., preparation of mononuclear cell fraction) performed under standard conditions. When appropriate, samples will be subjected to rate controlled freezing and stored in liquid nitrogen in a central facility under the supervision of Sample procurement Core Personnel. Either fresh or frozen samples will be delivered to the appropriate laboratories. These efforts will be supported by a core leader (Dr. Jeffrey Miller, M.D.) who is also an active investigator and research project leader (Project 2). The Sample procurement Core will serve as a resource for the entire program project which provides organization, integration, quality control and oversight coordinated by a single responsible core leader.